1. Technical Field
The present invention relates to gas turbine engines, commonly called jet engines, and more particularly to a thrust reverser system for use with a gas turbine engine.
2. Background Art
One reverser systems are generally known in the art for assisting in braking an aircraft during landing or in the event of an aborted takeoff attempt. Typical thrust reverser systems redirect a portion of the gases passing through the gas turbine engine in a forward direction, producing a force which acts on the aircraft opposing the direction of motion of the aircraft.
One thrust reverser purpose is to help an airplane decelerate on a runway which has been contaminated by ice, snow, or water. The incorporation of a traditional thrust reversing system on an engine designed to cruise at supersonic speeds can negatively impact the overall efficiency of the aircraft.
Currently, two common methods are utilized to provide reverse thrust in an airplane having a gas turbine engine, the "bucket" reverser and the "convergent blocker" reverser. Exemplary reverser bucket or blocker-type reverser systems are disclosed in U.S. Pat. Nos. 3,759,467 issued to Roudill; 3,837,411 issued to Nash; 3,943,707 issued to Nash; 4,373,328 issued Jones; 4,183,478 issued Rudolph; 4,185,798 issued to Dickinson; 4,353,516 issued to Soligny et al; and 5,507,143 issued to Luttgeharm. Exemplary "convergent blocker" reverser systems are disclosed in U.S. Pat. Nos. 3,262,270 issued Beavers; 3,603,090 issued to Billinger et al; 4,030,291 issued to Sargisson; 4,145,877 issued to Montgomery; 4,147,28 issued to Rodgers; 4,998,028 issued to Mutch; 5,228,641 issued to Remlaoui; and 5,575,147 issued to Nikkanen. Both the "bucket" reverser and the "convergent blocker" reverser typically involve the reversing of air from the high-temperature core stream of the engine. This requires the reverser components to be built from heavy and/or expensive heat-resistant materials which can tolerate the extreme temperatures of this environment.
In addition to requiring high-temperature materials for the thrust reverser components, these systems typically involve incorporation of high temperature materials in adjacent plane structures. These systems generally also include structure to help prevent the hot gases which leave the reverser from being undesirably reingested by the engine.
Convergent blocker type reversers often include convergent flaps to rotate to completely block the airflow and prevent it from escaping through the rear of the nozzle. This increases both the nozzle actuators stroke length and the total hydraulic power required to operate the nozzle.
Furthermore, the previously mentioned reverser systems are not easily integrated into a supersonic, variable-area nozzle. The length and complexity of the nozzle must be increased to accommodate the reverser system. This adds weight and may increase the external nozzle boattail angles, which may cause an increased drag on the engine.
Also of possible interest are U.S. Pat. Nos. 3,736,750 issued to Britt; and 3,841,091 issued to Sargisson et al.